U R T V 
have been eonfidered by many as zoophytes, or 
plant-animals. Some of the fpecies are found 
loofe on the fmooth ftiores, and others fixed to 
thofe rocks which are always covered with water. 
This has occafioned them to be divided into two 
claffesi a diftindlion as old as Ariftotle; thofe 
which move being called UrticE folutse, and re- 
ferred by Linnaeus to the genus of medufa, called 
alfo Urtica errans ; and fnch as are ufually fixed to 
the rocks, though capable of a locomotive power, 
being generally called Urtica Marina, and belong- 
ing to the Adlinia of Linnteus. 
Thefe creatures aflume fo many different forms, 
that it is impofTible to give any precife defcription 
of their figure. The moft: natural and general 
lhape feems to be that of a truncated cone, the 
bafe of which is applied to the rock; but this bafe 
is often round, often elliptic, and very frequently 
of a perfedlly irregular figure. The furface of the 
top of the cone is not flat, but convex; and has an 
aperture in it's centre, which the creature enlarges 
or contrails at pleafure. In fome pofitions, the 
whole fifli not unaptly refembles a purfe; with this 
difference only, that the body is not drawn up 
into any folds or wrinkles by the clofing of the 
aperture or mouth. In the middle of this purfe, 
as it may be called, is placed the body of the fifli, 
touching this exterior covering at the bottom on 
every fide. At it's top, however, it is loofe, and 
ftands every way clear of it's covering. The fides 
arc more or lefs difbant from this free or loofe part 
of the body, as the aperture of the top of the cone 
is more or lefs open : when it is nearly flnit up, 
very little of the body of the animal can be fccn ; 
but, when it opens it's mouth to different widths, 
more or lefs of the body becomes vifible; and, 
when it is at the wideft, every part of it, and all 
the horns, are feen perfeftly diflinft. Thefc horns 
refemble thofe of the common fnailj but, in their 
ufe, they feem more allied to the pipes or probof- 
ckles of the chamse kind, the fifh generally fpout- 
ing out water from them on being touched. They 
are arranged in three rows on the internal furface 
of the covering, and are very numerous; their 
whole number amounting to one hundred and 
fifty at leaft. 
The progreflive motion of this animal feems to 
be thus performed. When it has determined on 
it's route, it diftends all the tubes on that fide of 
it's body which is placed towards the point itwifhes 
to move to : this, from it's round fiiape at the bafe, 
gives it an oblong one; that is, it throws the fore- 
part fomewhat forward on the. rock; and at the 
fame time, if the tubes on the oppofite fide of the 
body be all left empty, and thofe which are natu- 
rally circular be diftended, thefe of confequence 
draw the whole body toward the fore-part, whereby 
a fmall advance is made and prefervedi and this 
being often repeated, gives a locomotive power to 
.the creature. All this, however, is performed fo 
very flowly, that though there is a continual 
change going on both as to figure and place, yet, 
if the eye is continually kept on the objeft, nei- 
ther is perceptible; but, if taken off for a fhort 
fpace, and the place and figure again inveftigated, 
both will be found different. 
The food of the Urtica Marina is no lefs Angu- 
lar than it's formation and motions. Strange as 
h may appear in an animal of this kind, it's con- 
ftant food is the flefh of mufclcs, fea-fnails, and 
. other fliell-fifh. It finds means to admit the fhell- 
■fifii whole into it's body, and then clofes the aper- 
URU 
turc fafi: upon it: here it keeps the prey as long as 
it pleafes, and then difcharges the empty fhell by 
the fame aperture, which it can contra6t or expand 
occafionally. By what means the Urtica is able 
to extraft the flefh from thefe fhell- fifh, is not 
known, as the whole procefs is performed within 
the body; certain, however, it is, that it frequently 
fails in the attempt, and is obliged to difgorge the 
fhell-fifh alive. 
It has been difcovered that this creature pof- 
feffes the remarkable reproductive quality of the 
polype. Reaumur tried various experiments on 
the different fpecies of this and the flar-fifh kind; 
and found that, whatever parts were amputated, 
the wound foon healed: and M. De Villars, who 
watched the v/hole progrefs of the growth of the 
amputated part, perceived that the animal not only 
appeared alive and healthy after cutting, but alfo 
foon regained what it had loft, and fpeedily be- 
came as perfect as before. 
Gaertner refers the Urtica Marina, or Sea-net- 
tle, to the Hydra of Linna:us, commonly called 
the polype; fince it agrees with that genus in the 
following general and cfTential charaders, as well 
as feveral fubordinate ones : it is of a gelatinous 
fubftance; it has only one aperture in it's body, 
which gives a pafl'age to it's food, as well as to it's 
excrements; and it has alfo a fet of feelers which 
furround this opening, ferving for claws to catch 
it's prey, and to convey it to it's mouth. 
The Greeks and Romans knew thefe animals 
under the appellations of Pneuma Thalafllos, and 
Pulmo marinus, or fea-lungs. They afcribed fe- 
veral medicinal virtues to them. Accordingly 
Diofcorides informs us, that they cure the gouC 
in the feet, and kibed heels, if rubbed frefh on the 
difeafed part : and ^lian fays they are fo depila- 
tory, that, if macerated in vinegar, they would ex- 
tirpate the very beard. Pliny remarks their phof- 
phoric quality ; and afTerts, that a ftick rubbed with 
them will feem to burn, and the whole wood to 
become lucid : he alfo adds that, when they fink to 
the bottom of the fea, they portend a continuance 
of bad weather. 
URUBU. A name by which fome ornitho- 
logifls have exprelTed the vulture. See Vul- 
ture. 
URUS. A fpecies of wild bull, of a very re- 
markable fize and flrength. Csefar, in his Com- 
mentaries, has defcribed it as little inferior to the 
elephant in fize; and refembling the bull in fhape, 
figure, and colour. He adds, that it is very fwifc 
and fierce; and has horns much larger, and very 
different from thofe of the common bull. 
The Urus, or Wild Bull, is now chiefly found 
in the province of Lithuania; and, according to 
Klein, arrives at a fize whieh fcarcely any other 
animal except the elephant is known to equal. 
It is quite black, except a ftripe, mixed with 
white, that runs from the neck to the tail along 
the ridge of the back ; the horns are fhort, thick, 
and ftrong; the eyes are fierce and fiery; thefore-^ 
head is adorned with a kind of garland of black 
curled hair, and fome varieties are found to have 
a beard of the fame; the neck is lliort and flrongj 
and the fkin has a mufl^y fmell. The female, 
though inferior in fize to the male, exceeds the 
largeft of our bulls in magnitude; neverthelefs, 
her udder and teats are fo Irnall, that they can 
fcarcely be perceived. On the whole, however, 
this animal refembles the tarne one very exaiftly, 
except in fome trifling varieties, which a ftatc of 
4 Y freedom. 
